Barbecue is favorite food of many people. A traditional barbecue oven generally includes a furnace body, an iron grid shelf set in an upper part of the furnace body and a fuel or charcoal receptacle placed on a bottom of the furnace body. Food supported on the iron grid is grilled directly on burning charcoal. During barbecuing, oil secreted from food and some condiments will drop directly onto the burning charcoal, which would generate flames and heavy smoke and make the food burnt. The gravy stuck to the iron grid will be burnt and become soot carbon, which would become carcinogens upon contacting food. In addition, the existing barbecue ovens are generally disadvantageous in that they consume a plenty of charcoal, only have single usage, and are not portable.